This Week's Guests:

• John Dau was one of the thousands of African males in southern Sudan attacked in the 1980s and '90s by the Arab Sudanese government in the north. For 16 years, Dau was either on the run—from Arab militia and the Sudanese Army, from wild animals, from starvation and thirst—or living in refugee camps. In 2001, he was among the lucky few chosen to immigrate to the United States, a place he had never heard of until he learned to read at the age of 17. He tells Boyd his story.

• The National Geographic Channel's Inside the Living Body offers a never-before-seen look on how the human body functions. Dr. Steven Palter, internationally recognized for his research, development and use of technologically advanced endoscopic procedures, was recruited to advise the makers of the documentary.

• David Doubilet is considered the leading underwater photographer in the world. He talks with Boyd about his trip to the reefs off Indonesia’s Raja Ampat Islands and the pictures he took for the September issue of National Geographic Magazine.

• While excavating an ancient Maya village in El Salvador buried by a volcanic eruption 1,400 years ago, Anthropologist Payson Sheets discovered an ancient field of manioc. Sheets tells Boyd what this first evidence for cultivation of the calorie-rich tuber in the New World means.

• Caitlin O'Connell-Rodwell has been listening to elephants in Africa and she tells Boyd that they can talk to each other through the ground! Using foot stomping and low-frequency rumbling they can generate seismic waves in the ground that can travel nearly 20 miles (32 kilometers) along the surface of the Earth.